Pipe cutting apparatus

ABSTRACT

An improvement in pipe cutting apparatus of the type having a number of cutting elements mounted for rotation on pins which also pivotally connect together the links of a roller type chain, means for tightening the chain around the pipe during a pipe cutting operation, and means for moving the chain around the pipe. The improvement resides in the fact that the chain tightening means is provided with parts which present co-acting guide surfaces adapted to align the ends of the chain length with respect to each other. Further, means are provided for adjusting the distance between the side links of each chain link and for locking the side links in the adjusted position.

United States Patent [1911 Axbjer PIPE CUTTING APPARATUS [76] Inventor:Erik Lennart Axbjer, Bultvagen 22,

Hagersten, Sweden 22 Filed: Jan l4, 1972 21 Appl. No.: 217,882

[30] Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS11/1950 Great Britain 30/100 Oct. 9, 1973 Primary ExaminerOthell M.Simpson Assistant Examiner-Mark S. Bicks Attorney-Eric H. Waters et a1.

[57] ABSTRACT An improvement in pipe cutting apparatus of the typehaving a number of cutting elements mounted for rotation on pins whichalso pivotally connect together the links of a roller type chain, meansfor tightening the chain around the pipe during a pipe cuttingoperation, and means for moving the chain around the pipe. Theimprovement resides in the fact that the chain tightening means isprovided with parts which present co-acting guide surfaces adapted toalign the ends of the chain length with respect to each other. Further,means are provided for adjusting the distance between the side links ofeach chain link and for locking the side links in the adjusted position.

4 Claims, 4 Drawing Figures PIPE CUTTING APPARATUS The present inventionrelates to an arrangement in pipe cutting apparatus of the typecomprising anumber of circular cutting elements mounted on a chain ofthe roller type which is capable of being placed around the pipe to becut and which has side links pivotally mounted on pins on which thecircular cutting elements, flanked by the side links, are mounted forrotation for cutting engagement with the pipe, tensioning means forconnecting together the ends of the length of chain utilized ineffectinga cutting operation and for tightening the chain around thepipe, and means connected to the tensioning means for causing the chainto move in the peripheral direction of the pipe, said means beingparticularly of the type capable of imparting a reciprocating movementto the chain and including attachment means secured to the pipe and adetachable linear piston engine capable of being coupled between theattachment means and the tensioning means.

An object of the present invention is to provide a new and usefularrangement in pipe cutting apparatus of the above described type,whereby such apparatus can be used for their intended purpose with theminimum of adjustment work and whereby the cutting precision of theapparatus can be retained in a relatively simple manner. i

To these ends it is proposed in accordance with the invention that withpipe cutting apparatus of the above described type the distance betweenthe side links of each chain link of the cutting chain be madeadjustable and that means be provided for maintaining the adjusteddistance between the links, and that the tensioning means components beprovided with co-acting guide surfaces arranged to bring the ends'of thechain into correct alignment with each other, thereby ensuring that allcutting elements are placed on and cut trated embodiment, are providedwith knurled or serrated surfaces 18 arranged to engage the outersurface of the pipe 11, and which are held in position by means of aroller chain 19, one end of the chain being'secured passes through ahole in a projection 22 on the arm 16,

along one andthe same line around the periphery of I the pipe.

' The invention will nowbe described in greater detail with reference toan embodiment thereof illustrated in the accompanying drawing, furtherfeatures of the invention being disclosed in connection therewith.

in the drawing, FIG. 1 illustrates in plan view a pipe cutting appatuspositioned on a pipe and including an arrangement according to theinvention.

HO. 2 is a side view of the apparatus shown in FIG. 1.

FIG. 3 is a fragmentary view in larger scale, illustrating a preferredarrangement for adjusting the distance between the side links of thechain of cutting elements.

FIG. 4 illustrates, partly diagrammatically, a device for causing thepiston in the linear piston engine to move backwards and forwards.

In the drawing, in which-like parts are identified with like referencenumerals, the numeral 10 indicates a cutting chain placed around a pipe11 to be cut. The reference numeral 12 indicates a tensioning means fortighting the chain around the pipe 11. The tensioning means 12 isconnected with a drive means, which in the illustrated embodimentcomprises an engine 14 and an engine attachment element 15, by means ofa pin 13 in a manner such as to enable the drive means to be readilydisconnected from the tensioning means.

The attachment 15 comprises a substantially V- shaped block having arms16 and 17 which, in the illuswhile screwed onto the spindle 21 on theside of the projection opposite the hook 20 is a nut 23, by means ofwhich the chain 19 can be tightened around the pipe 11, with theprojection 22 acting as an abutment surface, and therewith lock theV-block to the pipe. In the region where the arms l6, l7 meet, theV-block barries a pin 24 which extends parallel with the pipe 11 andwhich, for the purpose of connecting together the attachment 15 and theengine 14, is arranged to be accommodated in a complementary boredisposed in a bracket structure 25 which is securely connected to theengine 14.

The engine 14, which is in the form of a linear piston engine,preferably a pneumtatic piston-cylinder assembly, comprises a cylinder26 housing a piston (not shown), the piston rod of which is indicated bythe reference numeral 27. The piston rod 27 supports at its free end abifurcate member 28 arranged to be detachably connected to thetensioning means 12 by means of the pin 13, which passes through a holeof complementary configuration and size in the tensioning means and inthe legs of the bifurcate member 28. The engine 14 is thus arranged tobe pivotally connected to the tensioning means 12 and the attachment 15by .means of the pins 13 and 24 respectively in a manner to enable it tobe easily detached therefrom.

In the illustrated embodiment, the tensioning means 12 comprises mainlytwo parts in the form of arms 30, 31 pivotally connected together at oneend thereof by means of a pin 29. In accordance with the invention, theaforementioned parts of the tensioning means, in theillustrated instancethe arms 30, 31, have wide coacting' guide surfaces 32, 33, which ensurethat the arms when pivoting around the pin 29 constantly move in one andthe same plane extending at right angles to the pin. Specifically, asseen in FIG. 1, the arm 30 is formed with spaced lugs between which thearm 31 extends so that the co-acting guide surfaces 32,33 confront oneanother. At its end remote from the pin 29, the arm 30 is pivotallyconnected with one end of the cutting chain 10, for example by means ofa pin 34 which passes through the end of the arm 30 and the two sidelinks of the last chain link located at said one end of the chain 10.The other arm 31 of the tensioning means 12 is capable of beingdetachably connected at its end remote from the pin 29 with the otherend of the cutting chain, or with the length of chain utilized in theactual cutting operation in those instances, when the chain as a wholeis too long for the pipe to be cut. For the purpose of tightening thechain 10 around the pipe 11, there is arranged an externally threadedspindle 35, which is pivotally mounted in the arm 30 and which passesthrough a bore or a slot in the arm 31 and which carries on one end anut 36 arranged to cooperate with the side of the arm 31 remote from thearm 30 as an abutment surface and to be tightened during the pipecutting operation, as the cutting elements 37 cut into the pipe.

The cutting chain of the present invention is a roller type chain,having side links 38, 39 and pins 40 pivotally connecting the linkstogether and on which pins the circular cutting elements 37, flanked bythe side links 38, 39, are mounted for rotation for cutting engagementwith the pipev According to the invention, the distance between the sidelinks 38, 39 in each chain link of the cutting chain can be adjusted ina manner to maintain a high degree of precision of the cutting chaindespite the wear-and-tear experienced thereby. This feature, togetherwith the guide surfaces 32, 33 arranged on the tensioning means toensure that the ends of the chain 10, or of the length of chain used,are aligned correctly with respect to each other, makes certain that,when the chain 10 is placed around the pipe 11, all the cutting elements37 used in each cutting operation lie directly on and are caused to workalong one and the same line which extends around the periphery of thepipe and in a plane perpendicular to the axis of the pipe. For thepurpose of restricting the depth to which the cutting elements 37 areable to cut into the pipe 1] and to prevent the chain 10 from fasteningto the pipe 11, or a side link 38, 39 from rubbing against the pipe onsuch occasions when the cutting elements penetrate the pipe locallyaround the inner circumference thereof, there is preferably arranged oneither side of each cutting element a support roller 41. The supportrollers 41 are rotatably mounted on associated pins 40 and arepreferably located between the outermost side links 39, as illustratedin FIG. 3.

With the preferred embodiment of the cutting chain illustrated in FIG.3, adjustment of the distance between the side links is made possible bythe fact that each pin 40 is provided at one end thereof with apreferably cylindrical head 42 and at its other end 43 is in threadedengagement with the outmost side link 39 on the opposite side of thechain l0, thereby preventing the pin 40 from rotating relative the sidelinks 38, 39 together with the cutting elements 37, to avoid unnecessarywear-and-tear. To facilitate adjustment of the distance between the sidelinks 38, 39, the head 42 is suitably provided with a slot 44 or thelike for receiving a suitable turning tool, such as a screw driver. Theset position of the side links 38, 39 is locked by means of a lockingnut 45 located on the end 43 of the pin 40. The locking nut 45 ispreferably provided with a cylindrical outer surface such that withrespect to its external configuration the nut conforms substantiallywith the head 42, and is provided on only a limited portion thereof withspanner engaging surfaces or the like for cooperation with aconventional wrench for tightening the locking nut. In this connection,the end of the arm 31 remote from the pin 29 is preferably fork shaped,the limbs 46 of the fork being provided with hooks or recesses 47conforming to the heads 42 and the lock nuts 45 of the chain pins 40.

It lies within the purview of the invention to cause the cutting chain10 to move around the pipe 11 in one and the same direction when cuttingthe pipe. It is preferred, however, as will be evident from the drawing,to cause the cutting chain 10 to move backwards and forwardsperipherally around the pipe by means of a pressure cylinder or engine14, the length of stroke of the piston rod 27 being adjusted so thateach cutting element 37 moves through a distance which at least slightlyexceeds the distance between adjacent cutting elements. The cuttingchain 10 is suitably tightened, by

means of the nut 36, during the cutting operation, for example at theend of the outward stroke of the piston rod 27.

The known means for giving the piston rod 27 a continuous reciprocatingmovement is illustrated in FIG. 4,

in which the casing, indicated by the reference numeral 48 in FIG. 1,has been removed from the engine 14 to expose the engine components. Thepressure medium, in the illustrated example compressed air, used todrive the engine 14 enters through an inlet 49 which is provided with abayonet coupling and which leads to a conventional, pressure controlledthree-way directional valve 50, from which extend pipes 51 and 52 forconducting compressed air to the cylinder 26 on either side respectivelyof the piston (not shown) carrying the piston rod 27.

The directional valve is controlled by two conventional lowpressure-controlled diaphragm valves 53, 54, which, when the piston rod27 reaches its outermost and innermost positions, switches thecompressed air passage in the directional valve 50 so that compressedair is supplied to the cylinder 26 thorugh the line 52 or 51respectively. Working air is supplied to the valve 54 through a line 55,via a manually operated start valve 56, while working air is supplied tothe valve 53 through lines 57, 58 directly from the inlet 49. A line 59extending from the line 57 is arranged to conduct compressed air to thestart valve 56. The diaphragm valve 53, 54 detects the drop in pressurein the cylinder 26 at the end of the inward and outward stroke of thepiston, via the air lines 60 and 61 respectively, while working air fromthe valves 53 and 54 is passed to the directional valve 50 via the line62 and 63. With this arrangement the piston rod 27 will thus continue tomove backwards and forwards, provided that compressed air is suppliedthrough the inlet 49 and the operating button 64 of the start valve 56is in start position, while the piston rod 27 will stop at its innerposition, when the operating button 64 is moved to its stop position.

The invention is not restricted to the described and illustratedexample, but can be modified within the scope of the following claims.

I claim:

1. In an arrangement in pipe cutting apparatus of the type comprising anumber of circulr cutting elements mounted on a chain of the roller typewhich is capable of being placed around a pipe to be cut and which hasside links pivotally mounted on pins on which the circular cuttingelements, flanked by the side links, are mounted for rotation forcutting engagement with the pipe, tensioning means for connectingtogether the ends of the length of chain utilized in effecting a cuttingoperation and for tightening the chain around the pipe, and meansconnected to the tensioning means for causing the chain to movereciprocably in the peripheral direction of the pipe and includingattachment means secured to the pipe and a detachable linear pistonengine capable of being coupled between the attachment means and thetensioning means, an improvement comprising means for adjusting thedistance between the side links of each chain link and for locking theside links in the adjusted position, said tensioning means includingparts which are provided with co-acting guide surfaces arranged to bringthe ends of the chain into correct alignment with each other, therebyensuring that all cutting elements are placed on and cut along one andthe same line around the periphery of the pipe.

depth to which the cutting elements cut into the pipe.

4. An arrangement according to claim 1 wherein said parts with theco-acting guide surfaces include two pivotably connected arms eachconnected to a respective end of the chain, one of said arms includingspaced lugs, the other arm being fitted between said lugs, saidco-acting guide surfaces being constituted by flat abutment surfaces infacing contact on said lugs and other arm.

1. In an arrangement in pipe cutting apparatus of the type comprising anumber of circulr cutting elements mounted on a chain of the roller typewhich is capable of being placed around a pipe to be cut and which hasside links pivotally mounted on pins on which the circular cuttingelements, flanked by the side links, are mounted for rotation forcutting engagement with the pipe, tensioning means for connectingtogether the ends of the length of chain utilized in effecting a cuttingoperation and for tightening the chain around the pipe, and meansconnected to the tensioning means for causing the chain to movereciprocably in the peripheral direction of the pipe and includingattachment means secured to the pipe and a detachable linear pistonengine capable of being coupled between the attachment means and thetensioning means, an improvement comprising means for adjusting thedistance between the side links of each chain link and for locking theside links in the adjusted position, said tensioning means includingparts which are provided with co-acting guide surfaces arranged to bringthe ends of the chain into correct alignment with each other, therebyensuring that all cutting elements are placed on and cut along one andthe same line around the periphery of the pipe.
 2. An arrangementaccording to claim 1, wherein each pin includes at one end thereof acylindrical head the other end of said pin being in threaded engagementwith the outermost side link on the opposite side of the cutting chain,and means comprising a cylindrical locking nut mounted on the end of thepin projecting outwardly of said outermost side link, to preventrotation of the pin together with the circular cutting element.
 3. Anarrangement according to claim 1 support rollers mounted for rotation onthe pins for restricting the depth to which the cutting elements cutinto the pipe.
 4. An arrangement according to claim 1 wherein said partswith the co-acting guide surfaces include two pivotably connected armseach connected to a respective end of the chain, one of said armsincluding spaced lugs, the other arm being fitted between said lugs,said co-acting guide surfaces being constituted by flat abutmentsurfaces in facing contact on said lugs and other arm.